Just the standard "i'm going to make the word LOL hover in the air", followed by "Fuck it lets put Nyan Cat up there too":

A neat effect is that you have very little depth reference, so spinning wireframes appear a little more 3d than usual

Another test, but with some simple scrolling text. You can see how the stream is breaking up and fuzzing the text, I'd trimmed the length of the straws here which I think has ruined it!

So a bit about the construction of this, at the moment the prototype is made out of:

A PC fan (to generate some airflow)

A thin line of drinking straws (to generate a laminar flow)

Some sponge (to smooth the flow from the fan)

Margarine container (for the actual air chamber

Ultrasonic Fogger (to make the fog)

Essentially all that happens is that the fogger generates some mist in the margarine container, this is pumped up the straws by the fan. After travelling down the length of the straws the airflow is fairly laminar (see here for an explanation of what laminar flow is) and it produces a nice flat sheet of water mist in the air. The water mist is pretty much invisible in the dark but if you aim a projector at it from behind the image appears in the air. In the case of the "LOL" image above the black background is transparent and the words appear to hang in the air

Theres a lot to be improved on this prototype, the laminar flow breaks up after about 10-15 cm and ruins the image at the top of the projection. I think that can be fixed with a curtain of air either side (as the professional machines do), if that doesnt work I'll mess with the straw diameters and airflow speeds to try and get it more stable.I have plans to lasercut a proper enclosure for this on the lasercutter at the London hackspace soon, couple with a proper set of tubes for the laminar flow generation and it should work a lot better

Also, on the "laminar air flow" experiments front: all hail hovercube!